CN106612070B - A kind of the load transient response Enhancement Method and system of voltage-mode buck converter - Google Patents
A kind of the load transient response Enhancement Method and system of voltage-mode buck converter Download PDFInfo
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- CN106612070B CN106612070B CN201510690108.2A CN201510690108A CN106612070B CN 106612070 B CN106612070 B CN 106612070B CN 201510690108 A CN201510690108 A CN 201510690108A CN 106612070 B CN106612070 B CN 106612070B
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0016—Control circuits providing compensation of output voltage deviations using feedforward of disturbance parameters
- H02M1/0019—Control circuits providing compensation of output voltage deviations using feedforward of disturbance parameters the disturbance parameters being load current fluctuations
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Abstract
The invention discloses a kind of load transient response Enhancement Methods of voltage-mode buck converter, comprising: carries out low-pass filtering to the output voltage Vout of voltage-mode buck converter, generates average voltage Vout1；The difference of Vout and Vout1 is calculated, and carries out the amplitude waveform for the difference being calculated to be converted to fluctuating current Itran；Slope processing is carried out to the amplitude of fluctuating current Itran, the transient response output voltage Vout of voltage-mode buck converter is generated according to obtained ramp signal.The present invention further simultaneously discloses a kind of load transient response enhancing system of voltage-mode buck converter.
Description
Technical Field
The present invention relates to circuit electronics, and more particularly, to a method and system for enhancing transient response of a voltage-mode buck converter.
Background
With the rapid development of various electronic product markets, a power chip technology capable of providing stable voltage for electronic products is also continuously advanced. The load of the power supply chip is various, the change of the load size is inevitable, and the transient response time and the transient response capability of the load become key technical indexes for measuring the excellence of the power supply chip. In order to ensure the accuracy range of the output voltage of the power supply chip, the power supply chip is required to have good load transient response capability.
Buck converters are used primarily in situations where the input voltage is relatively high and the output voltage is relatively low. The general voltage-mode buck converter mainly comprises an oscillator, a ramp generator, an error amplifier, a compensation network, a pulse width generator, a logic control, a driving and power switch, an output filter, a feedback network and a plurality of protection modules. The fixed frequency is generated by an oscillator, and a logic part and a power tube switch are synchronously controlled; the ramp generator generates a ramp signal for pulse width control; the feedback network, the error amplifier and the compensation network form a control core of the converter and are used for amplifying the output voltage change; the ramp signal and the error amplifier signal are compared by a pulse width generator to generate a pulse width control signal; the pulse width control signal is combined with the oscillator signal to generate a duty ratio through a logic and power switch, the duty ratio controls the output power tube to be switched on and off, and stable voltage is output after the output power tube passes through a filter network.
The traditional buck converter can output stable voltage and can meet the application scene of small load change or slow load change; when the load changes rapidly or the voltage stability requirement of the later stage is high, the traditional structure is difficult to meet the design requirement, so that the structure needs to be changed or an additional circuit needs to be added to enhance the load response capability.
Disclosure of Invention
In order to overcome the defects of the prior art, embodiments of the present invention are expected to provide a method and a system for enhancing a load transient response of a voltage-mode buck converter, which can greatly improve the load transient response capability of the voltage-mode buck converter and effectively improve the accuracy of an output voltage caused by load change.
The technical scheme of the embodiment of the invention is realized as follows:
a method of load transient response enhancement for a voltage-mode buck converter, the method comprising:
low-pass filtering the output voltage Vout of the voltage-mode buck converter to generate an average voltage Vout 1;
calculating the difference value between Vout and Vout1, and converting the amplitude waveform of the calculated difference value to obtain a fluctuation current Itran;
and performing ramp processing on the amplitude value of the fluctuating current Itran, and generating a transient response output voltage Vout of the voltage-mode buck converter according to the obtained ramp signal.
Preferably, the ramp processing of the amplitude of the ripple current Itran, and the generation of the transient response output voltage Vout of the voltage-mode buck converter according to the obtained ramp signal, includes:
firstly, performing slope processing on the amplitude of the fluctuation current Itran to generate a feedback tooth-shaped voltage Vramp; and then, according to the pulse width of the feedback tooth-shaped voltage Vramp in a unit period, the transient response output voltage Vout of the voltage mode buck converter is generated by modulation.
Preferably, the method further comprises: presetting a first input threshold voltage delta V1 and a second input threshold voltage delta V2;
the converting the amplitude waveform of the calculated difference value to obtain the ripple current Itran includes:
when Vout-Vout1 is larger than Δ V1, converting the amplitude waveform of Vout-Vout1- Δ V1 into a fluctuation current Itran of a corresponding waveform, wherein the obtained fluctuation current Itran is a forward current;
when the difference between Vout and Vout1 is greater than zero and less than Δ V1, no ripple current Itran is generated;
when Vout1-Vout is larger than Δ V2, converting the amplitude waveform of Vout1-Vout- Δ V2 into a fluctuation current Itran of a corresponding waveform, wherein the obtained fluctuation current Itran is a reverse current;
when the difference between Vout1-Vout is greater than zero and less than Δ V2, no ripple current Itran is generated.
Preferably, the generating the feedback tooth voltage Vramp includes:
and superposing the fluctuating current Itran and a preset reference current Iref to generate a feedback current Iramp, and generating a feedback tooth-shaped voltage Vramp according to the amplitude of the feedback current Iramp.
Preferably, the method further comprises: generating a rectangular wave for modulation according to the difference value of the feedback tooth-shaped voltage Vramp and the feedback voltage Vcomp; the feedback voltage Vcomp is obtained by amplifying a difference between the reference voltage Vref and the divided output voltage Vout, and a portion of the feedback tooth-shaped voltage Vramp that is greater than the feedback voltage Vcomp is a high-level portion of the rectangular wave.
Preferably, the first input threshold voltage Δ V1 and the second input threshold voltage Δ V2 are offset voltages of the first voltage comparison operational amplifier and the second voltage comparison operational amplifier in sequence; the offset voltage is a preset fixed value and is generated by asymmetry of output stages of two output MOS tubes of a transconductance operational amplifier of the voltage comparison operational amplifier.
A load transient response enhancement system for a voltage-mode buck converter, the system comprising a low-pass filter, a voltage comparison op-amp, a ramp generator and a voltage generating means; wherein,
the low-pass filter is used for performing low-pass filtering on the output voltage Vout of the voltage-mode buck converter to generate an average voltage Vout 1;
the voltage comparison operational amplifier is used for calculating the difference value between Vout and Vout1, and converting the amplitude waveform of the calculated difference value to obtain a fluctuation current Itran;
the slope generator is used for performing slope processing on the amplitude of the fluctuation current Itran;
and the voltage generating device is used for generating the transient response output voltage Vout of the voltage-mode buck converter according to the obtained ramp signal.
Preferably, the voltage comparison op-amp comprises: the first voltage comparison operational amplifier and the second voltage comparison operational amplifier;
the first voltage comparison operational amplifier presets a first input threshold voltage delta V1, and the second voltage comparison operational amplifier presets a second input threshold voltage delta V2;
when the Vout-Vout1- Δ V1 is greater than zero, the first voltage comparison operational amplifier works, and the first voltage comparison operational amplifier outputs a forward ripple current Itran according to the amplitude of the Vout-Vout1- Δ V1;
when the Vout1-Vout- Δ V2 is greater than zero, the second voltage comparison operational amplifier operates, and the second voltage comparison operational amplifier outputs a reverse ripple current Itran according to the amplitudes of the Vout1-Vout- Δ V2.
Preferably, the ramp generator is specifically configured to superimpose the ripple current iran and a preset reference current Iref to generate a feedback current Iramp, and generate the feedback tooth voltage Vramp according to an amplitude of the feedback current Iramp.
Preferably, the system further comprises an error amplifier EA for generating a feedback voltage Vcomp from the reference voltage Vref and the divided output voltage Vout;
correspondingly, the voltage generating device is configured to generate a pulse width signal according to a difference between the feedback tooth-shaped voltage Vramp and the feedback voltage Vcomp, and modulate the pulse width signal to generate the transient response output voltage Vout of the voltage-mode buck converter.
Preferably, the system further comprises a compensation network compensation, and the feedback voltage Vcomp is a voltage compensated by the compensation network compensation.
Preferably, the first voltage comparison operational amplifier and the second voltage comparison operational amplifier both comprise a transconductance operational amplifier and a mirror current circuit;
the output stages of the two output MOS tubes of the transconductance operational amplifier are asymmetric to generate offset voltage; the first input threshold voltage delta V1 and the second input threshold voltage delta V2 are offset voltages of the first voltage comparison operational amplifier and the second voltage comparison operational amplifier in sequence;
the mirror current circuit is located at the output end of the voltage comparison operational amplifier, and the current of the mirror current circuit is unidirectional.
According to the method and the system for enhancing the load transient response of the voltage-mode buck converter, provided by the embodiment of the invention, the output voltage Vout of the voltage-mode buck converter is subjected to low-pass filtering to generate an average voltage Vout1, the difference between the Vout and the Vout1 is calculated, and the amplitude waveform of the calculated difference is converted into a fluctuating current; then, performing ramp processing on the amplitude of the fluctuating current, and generating a transient response output voltage Vout of the voltage mode buck converter according to the obtained ramp signal so as to realize real-time feedback regulation on the value of the output voltage Vout of the voltage mode buck converter; the embodiment of the invention has simple structure and quick response, can greatly improve the load transient response capability of the voltage-mode buck converter, can effectively solve the problem of poor load transient response during voltage-mode buck, and can effectively solve the problem of accuracy of output voltage caused by load change.
Drawings
FIG. 1 is a schematic process flow diagram illustrating a method for enhancing a load transient response of a voltage-mode buck converter according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a load transient response enhancement system of a voltage-mode buck converter according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a first voltage comparison operational amplifier according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a second voltage comparison operational amplifier according to an embodiment of the present invention;
FIG. 5 is a schematic structural diagram of a ramp generator ramp according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of a transient waveform when the load is dropped according to an embodiment of the present invention;
fig. 7 is a schematic diagram of a transient variation waveform when a load rises according to an embodiment of the present invention.
Detailed Description
In the embodiment of the invention, the output voltage Vout of the voltage-mode buck converter is low-pass filtered to generate an average voltage Vout 1; calculating the difference between Vout and Vout1, and converting the amplitude waveform of the obtained difference to obtain a fluctuation current Itran; and performing ramp processing on the amplitude value of the fluctuating current Itran, and generating a transient response output voltage Vout of the voltage-mode buck converter according to the obtained ramp signal.
Here, the ramp generating a transient response output voltage Vout of the voltage-mode buck converter includes: firstly, performing slope processing on the amplitude of the fluctuation current Itran to generate a feedback tooth-shaped voltage Vramp; and then, according to the pulse width of the feedback tooth-shaped voltage Vramp in a unit period, the transient response output voltage Vout of the voltage mode buck converter is generated by modulation.
The present invention will be described in further detail with reference to the accompanying drawings and examples.
As shown in fig. 1, a processing flow of the method for enhancing a load transient response of a voltage-mode buck converter provided by an embodiment of the present invention includes the following steps:
s1: low pass filtering (low pass filtering to R11 and C11) the output voltage Vout of the voltage-mode buck converter, generating an average voltage Vout 1;
s2: calculating the difference value between Vout and Vout1, and converting the amplitude waveform of the calculated difference value to obtain a fluctuation current Itran;
here, the voltage comparison op-amp may be used to perform current conversion on the magnitude waveform of the difference of Vout minus Vout1, specifically: the voltage comparison operational amplifier firstly calculates the difference between Vout and Vout1, and converts the calculated amplitude curve into the current curve of the corresponding waveform.
S3: performing ramp processing on the amplitude value of the fluctuation current Itran, and generating a transient response output voltage Vout of the voltage mode buck converter according to an obtained ramp signal;
the method specifically comprises the following steps: firstly, performing slope processing on the amplitude of the fluctuation current Itran to generate a feedback tooth-shaped voltage Vramp; and then, according to the pulse width of the feedback tooth-shaped voltage Vramp in a unit period, the transient response output voltage Vout of the voltage mode buck converter is generated by modulation.
Here, a ramp generator ramp may be used for ramp processing, and a capacitor of the ramp generator ramp is periodically charged by a fluctuating current Itran to obtain a voltage ramp curve in the unit period; the larger the forward output current at a certain time is, the larger the slope of the voltage slope of the capacitor is, and conversely, the smaller the slope of the voltage slope of the capacitor is.
Meanwhile, a pulse width generating device of the voltage generating device can be adopted to perform rectangular wave processing on the feedback tooth-shaped voltage Vramp to obtain a corresponding pulse width; the transient response output voltage Vout of the voltage-mode buck converter is generated by the pulse width modulation of the logic drive circuit. Specifically, the feedback tooth-shaped voltage Vramp may be compared with a base value preset by the voltage-mode buck converter or fed back according to the output voltage Vout, and a portion of Vramp larger than the base value is a high level of a rectangular wave, so as to obtain a corresponding pulse width, and modulate the pulse width to generate the transient response output voltage Vout.
To further more accurately obtain the output ripple current Itran, a first input threshold voltage Δ V1 and a second input threshold voltage Δ V2 may be preset; correspondingly, the converting the amplitude waveform of the calculated difference value to obtain the ripple current Itran includes:
when Vout-Vout1 is larger than Δ V1, converting the amplitude waveform of Vout-Vout1- Δ V1 into a fluctuation current Itran of a corresponding waveform, wherein the obtained fluctuation current Itran is a forward current;
when the difference of Vout-Vout1 is greater than zero but less than Δ V1, no ripple current Itran is generated;
when Vout1-Vout is larger than Δ V2, converting the amplitude waveform of Vout1-Vout- Δ V2 into a fluctuation current Itran of a corresponding waveform, wherein the obtained fluctuation current Itran is a reverse current;
when the difference between Vout1-Vout is greater than zero but less than Δ V2, no ripple current Itran is generated.
Here, the first input threshold voltage Δ V1 and the second input threshold voltage Δ V2 are offset voltages of the first voltage comparison operational amplifier and the second voltage comparison operational amplifier, respectively, where the offset voltage is a preset fixed value, and the offset voltages are generated asymmetrically at output stages of two output MOS transistors of a transconductance operational amplifier of the voltage comparison operational amplifier. The ripple current Itran is a mirror current capable of driving other devices.
The ripple current Itran and a preset reference current Iref are superposed to generate a feedback current Iramp, and a feedback tooth-shaped voltage Vramp is generated according to the amplitude of the feedback current Iramp. Further, a rectangular wave for modulation may be generated according to a difference between the feedback tooth voltage Vramp and the feedback voltage Vcomp (i.e., a preset base value of the voltage-mode buck converter), so as to adjust the output duty ratio. The feedback voltage Vcomp is obtained by amplifying the difference value of the reference voltage Vref and the output voltage Vout after voltage reduction, and the part of the feedback tooth-shaped voltage Vramp which is larger than the feedback voltage Vcomp is the high-level part of the rectangular wave; the feedback voltage Vcomp is compensated, and the compensation voltage can make the waveform of the feedback voltage Vcomp more gentle.
As shown in fig. 2, a system for enhancing transient response of a load of a voltage-mode buck converter according to an embodiment of the present invention includes: the device comprises a low-pass filter, a voltage comparison operational amplifier, a ramp generator ramp and a voltage generating device; wherein,
the low-pass filter comprises C11 and R11 and is used for low-pass filtering the output voltage Vout of the voltage-mode buck converter to generate an average voltage Vout 1;
the voltage comparison operational amplifier is used for calculating the difference value between Vout and Vout1, and converting the amplitude waveform of the calculated difference value to obtain a fluctuation current Itran;
the slope generator is used for performing slope processing on the amplitude of the fluctuation current Itran;
and the voltage generating device is used for generating the transient response output voltage Vout of the voltage-mode buck converter according to the obtained ramp signal.
Specifically, the ramp generator performs ramp processing on the amplitude of the fluctuation current Itran to generate a feedback tooth-shaped voltage Vramp;
correspondingly, the voltage generating device is configured to generate a pulse width signal according to a difference between the feedback tooth-shaped voltage Vramp and the feedback voltage Vcomp, and modulate the pulse width signal to generate a transient response output voltage Vout of the voltage-mode buck converter;
the voltage generating device can further comprise a pulse width generating device PWM and a Logic + Driver circuit (Logic + Driver), the pulse width generating device carries out rectangular wave processing on the feedback tooth-shaped voltage Vramp, and a corresponding pulse width is obtained according to the difference value of the feedback tooth-shaped voltage Vramp and the feedback voltage Vcomp; the resulting pulse width is modulated by a logic drive circuit to generate the transient response output voltage Vout of the voltage-mode buck converter.
The voltage comparison operational amplifier comprises a first voltage comparison operational amplifier gm1 and a second voltage comparison operational amplifier gm2, and the specific structure refers to fig. 3 and 4; the first voltage comparison operational amplifier gm1 presets a first input threshold voltage Δ V1, and the second voltage comparison operational amplifier gm2 presets a second input threshold voltage Δ V2;
correspondingly, the voltage comparison operational amplifier converts the amplitude waveform of the calculated difference value to obtain the ripple current Itran, which specifically includes:
when the Vout-Vout1- Δ V1 is greater than 0, the first voltage comparison operational amplifier operates, and the first voltage comparison operational amplifier outputs a forward ripple current Itran according to the amplitude of the Vout-Vout1- Δ V1, namely: the direction of the current flowing out of the first voltage comparison operational amplifier is positive;
when the Vout1-Vout- Δ V2 is greater than 0, the second voltage comparison operational amplifier operates, and the second voltage comparison operational amplifier outputs a reverse ripple current Itran according to the amplitudes of the Vout1-Vout- Δ V2, namely: the direction of current flowing into the second voltage comparison operational amplifier is reverse.
The first voltage comparison operational amplifier gm1 and the second voltage comparison operational amplifier gm2 both comprise a transconductance operational amplifier and a mirror current circuit, and output stages of two output MOS (metal oxide semiconductor) tubes of the transconductance operational amplifier asymmetrically generate offset voltage; the first input threshold voltage delta V1 and the second input threshold voltage delta V2 are offset voltages of the first voltage comparison operational amplifier and the second voltage comparison operational amplifier in sequence; the mirror current circuit is positioned at the output end of the voltage comparison operational amplifier, and the current in the mirror current circuit is unidirectional. The ripple current Itran is a mirror current capable of driving other devices.
Specifically, referring to fig. 3, in the design of the first voltage comparison operational amplifier gm1, when the output stages M16 are n-1 and M18 are n, the number of the output stages is different, so that the output terminals generate a fixed offset voltage, i.e., the first input threshold voltage Δ V1. When the transient variation value of Vout (Vout-Vout1) is smaller than Δ V1, gm1 is in a large signal operating state, and since the MOS transistor output stage M18 near VIN is higher than M16, the voltage output point Vgm1 is VIN, and at this time, the output ripple current Itran is 0; when the transient variation value of Vout (Vout-Vout1) is greater than Δ V1, i.e., Vout becomes high instantaneously, the larger the value of Vout-Vout1 is, the voltage at the voltage output point Vgm1 decreases, and the difference between VIN and Vgm1 causes M19 and M10 to be turned on, so that the first voltage comparison operational amplifier gm1 is in an amplified state. M19 and M10 constitute a mirror current circuit, the amplitude of the output voltage Vgm1 controls the current size of M19, and the larger the input voltage difference (Vout-Vout1), the lower the amplitude of the output voltage Vgm1, and the larger the output current (Itran). For the part generating the offset voltage, the number of MOS transistors in the M11 and M12 parts of the input stage may not be matched, so as to generate the offset voltage Δ V1. The first voltage comparison operational amplifier gm1 can only operate when Vout-Vout1 is greater than Δ V1, and if it is less than Δ V1, the MOS transistor of the mirror current circuit is in a reverse cut-off state.
The structure of the second voltage comparison operational amplifier gm2 is shown in fig. 4, and similarly, the structure is similar to that of the first voltage comparison operational amplifier, and the main difference is that the voltage reference points of the mirror current circuit are different, specifically: at design time, the output stage M26 is n, and M28 is n-1, which generates a fixed offset voltage, i.e., the second input threshold voltage Δ V2. When the transient variation difference value of Vout (Vout1-Vout) is smaller than Δ V2, gm2 is in a large signal working state, because the MOS tube output stage M26 close to the ground end is higher than M28, the value of the voltage output point Vgm2 is GND, and the output ripple current Itran is 0 at this moment; when the transient variation value of Vout (Vout1-Vout) is larger than the Δ V2, that is, when Vout becomes low instantaneously, the larger the value of Vout1-Vout, the higher the voltage of the voltage output point Vgm2, the difference between Vgm2 and the ground line makes M29 and M20 conduct, so that the second voltage comparison operational amplifier gm2 is in an amplification state. M19 and M10 constitute a mirror current circuit, the amplitude of the output voltage Vgm2 controls the current size of M19, and the larger the input voltage difference (Vout1-Vout), the higher the amplitude of the output voltage Vgm2, and the larger the output current (Itran). For the part generating the offset voltage, the number of MOS transistors in the M21 and M22 parts of the input stage may not be matched, so as to generate the offset voltage Δ V2. The second voltage comparison operational amplifier gm2 can only work when Vout1-Vout is larger than Δ V2, and if the Vout is smaller than Δ V2, the MOS transistor of the mirror current circuit is in a reverse cut-off state.
As shown in fig. 5, a schematic structural diagram of a ramp generator ramp according to an embodiment of the present invention, where the ramp generator ramp generates a ramp signal by charging and discharging C1 and C2, respectively. The duty cycle of the Clk1 clock of an embodiment of the present invention is 50%, which is divided by the Clk clock 2. When the rising edge of clk1 arrives, s1 opens, s2 closes, and Buf drives C1 so that the voltage of C1 equals Vref. When the falling edge of clk1 comes, s1 is closed, s2 is opened, and Buf 1 drives C2 to make the voltage of C2 equal to Vref; at this point C1 has begun to be charged by the feedback current Iramp and produces the feedback ripple Vramp. When the next rising edge of clk1 comes, s1 opens, s2 closes, and Buf drives C1 so that the voltage of C1 equals Vref; at this point C2 has begun to be charged by the feedback current Iramp and produces the feedback ripple Vramp.
Therefore, the initial voltage of the capacitor is stabilized by charging the capacitor in the time of one clk clock period of Buf in a mode of alternately switching the charge and discharge capacitors, the situation that the single capacitor starts to use to generate the ramp voltage when the voltage is not stabilized at the switching moment can be prevented, the situation that the initial voltages of two continuous ramp signals are not equal is avoided, and the duty ratio of the PWM wave is inaccurate.
Because the amplitude of the fluctuating current Itran is low, the fluctuating current Itran is inconvenient to directly apply and has weak loading capacity, the ramp generator ramp first superimposes the fluctuating current Itran and a preset reference current Iref to generate a feedback current Iramp, and then generates a feedback tooth-shaped voltage Vramp according to the amplitude of the feedback current Iramp.
Similarly, the system further comprises an Error Amplifier (EA), and the reference voltage Vref and the output voltage Vout after being reduced generate a feedback voltage Vcomp through the error amplifier; correspondingly, the pulse width generating device generates a rectangular wave for modulation according to the difference value between the feedback tooth-shaped voltage Vramp and the feedback voltage Vcomp, and the part of the feedback tooth-shaped voltage Vramp which is larger than the feedback voltage Vcomp is the high level part of the PWM.
The system further comprises a compensation network compensation, and the feedback voltage Vcomp is a voltage compensated by the compensation network compensation, so that the feedback voltage Vcomp forms a gentle waveform.
As shown in FIG. 6, wherein Iload is the load current and IL is the inductor current (the current of inductor L in FIG. 2). When the load current Iload suddenly decreases, the filter network (the power filter network composed of Co and L in fig. 2) cannot maintain Vout stable, and the Vout voltage rapidly rises; when the voltage difference between Vout and Vout1 is greater than the first input threshold voltage Δ V1 of the first voltage comparison operational amplifier gm1, the voltage at the voltage output point Vgm1 drops, thereby controlling the generation of the ripple current Itran corresponding to the voltage difference, where the generation process of the current is similar to the previous principle and will not be described again.
The reference current Iref and the ripple current Itran are superposed to generate a feedback current Iramp, the feedback current Iramp increases, and specifically, if the direction of the first voltage comparison operational amplifier is taken as the positive direction, the positive direction is the direction of current increase, which is equivalent to that the current is injected into the reference current Iref, so that the reference current increases; meanwhile, the slope of the generated feedback tooth-shaped voltage Vramp signal is increased; the feedback tooth-shaped voltage Vramp is compared with the feedback voltage Vcomp to form PWM waves, and the slope of the feedback tooth-shaped voltage Vramp is larger, so that the pulse width of the output PWM waves is larger, the duty ratio SW is reduced due to the control of hd and ld, the inductive current IL is rapidly reduced, meanwhile Vout is reduced, and the purpose of rapidly adjusting the output voltage Vout is achieved.
As shown in FIG. 7, wherein Iload is the load current and IL is the inductor current (the current of inductor L in FIG. 2). When the load current Iload suddenly increases, the filter network (the power filter network composed of Co and L in fig. 2) cannot maintain Vout stable, and the Vout voltage rapidly drops; when the voltage difference between Vout1 and Vout is greater than the second input threshold voltage Δ V2 of the second voltage comparison operational amplifier gm2, the voltage at the voltage output point Vgm2 rises, so as to control the generation of the ripple current Itran corresponding to the voltage difference, where the generation process of the current is similar to the previous principle and will not be described again here.
The reference current Iref and the fluctuating current Itran are superposed to generate a feedback current Iramp, the feedback current Iramp is reduced in current, and specifically, if the direction of the current flowing into the first voltage comparison operational amplifier is negative, the negative direction is the direction of current reduction, which is equivalent to the current being extracted out of the reference current Iref, the reference current is reduced; meanwhile, the slope of the generated feedback tooth-shaped voltage Vramp slope signal is reduced; the feedback tooth-shaped voltage Vramp is compared with the feedback voltage Vcomp to form PWM waves, and the slope of the feedback tooth-shaped voltage Vramp is small, the pulse width of the output PWM waves is small, so that the duty ratio SW is small due to the control of hd and ld, the inductive current IL is quickly increased, meanwhile Vout is increased, and the purpose of quickly adjusting the output voltage Vout is achieved.
The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, and any modifications, equivalents, improvements, etc. that are within the spirit and principle of the present invention should be included in the present invention.
Claims (11)
1. A method of load transient response enhancement for a voltage-mode buck converter, the method comprising:
low-pass filtering the output voltage Vout of the voltage-mode buck converter to generate an average voltage Vout 1;
calculating the difference value between Vout and Vout1, and converting the amplitude waveform of the calculated difference value to obtain a fluctuation current Itran;
performing slope processing on the amplitude of the fluctuation current Itran to generate a feedback tooth-shaped voltage Vramp; and then, according to the pulse width of the feedback tooth-shaped voltage Vramp in a unit period, the transient response output voltage Vout of the voltage mode buck converter is generated by modulation.
2. The method of claim 1, further comprising: presetting a first input threshold voltage delta V1 and a second input threshold voltage delta V2;
the converting the amplitude waveform of the calculated difference value to obtain the ripple current Itran includes:
when Vout-Vout1 is larger than Δ V1, converting the amplitude waveform of Vout-Vout1- Δ V1 into a fluctuation current Itran of a corresponding waveform, wherein the obtained fluctuation current Itran is a forward current;
when the difference between Vout and Vout1 is greater than zero and less than Δ V1, no ripple current Itran is generated;
when Vout1-Vout is larger than Δ V2, converting the amplitude waveform of Vout1-Vout- Δ V2 into a fluctuation current Itran of a corresponding waveform, wherein the obtained fluctuation current Itran is a reverse current;
when the difference between Vout1-Vout is greater than zero and less than Δ V2, no ripple current Itran is generated.
3. The method of claim 1, wherein the generating the feedback tooth voltage Vramp comprises:
and superposing the fluctuating current Itran and a preset reference current Iref to generate a feedback current Iramp, and generating a feedback tooth-shaped voltage Vramp according to the amplitude of the feedback current Iramp.
4. The method of claim 3, further comprising: generating a rectangular wave for modulation according to the difference value of the feedback tooth-shaped voltage Vramp and the feedback voltage Vcomp; the feedback voltage Vcomp is obtained by amplifying a difference between the reference voltage Vref and the divided output voltage Vout, and a portion of the feedback tooth-shaped voltage Vramp that is greater than the feedback voltage Vcomp is a high-level portion of the rectangular wave.
5. The method of claim 2, wherein the first input threshold voltage Δ V1 and the second input threshold voltage Δ V2 are sequentially offset voltages of the first voltage comparison operational amplifier and the second voltage comparison operational amplifier; the offset voltage is a preset fixed value and is generated by asymmetry of output stages of two output MOS tubes of a transconductance operational amplifier of the voltage comparison operational amplifier.
6. A load transient response enhancement system of a voltage-mode buck converter, the system comprising a low-pass filter, a voltage comparison op-amp, a ramp generator, and a voltage generating device; wherein,
the low-pass filter is used for performing low-pass filtering on the output voltage Vout of the voltage-mode buck converter to generate an average voltage Vout 1;
the voltage comparison operational amplifier is used for calculating the difference value between Vout and Vout1, and converting the amplitude waveform of the calculated difference value to obtain a fluctuation current Itran;
the ramp generator is used for performing ramp processing on the amplitude of the fluctuation current Itran to generate a feedback tooth-shaped voltage Vramp;
and the voltage generating device is used for modulating and generating the transient response output voltage Vout of the voltage mode buck converter according to the pulse width of the feedback tooth-shaped voltage Vramp in a unit period.
7. The system of claim 6, wherein the voltage comparison op-amp comprises: the first voltage comparison operational amplifier and the second voltage comparison operational amplifier;
the first voltage comparison operational amplifier presets a first input threshold voltage delta V1, and the second voltage comparison operational amplifier presets a second input threshold voltage delta V2;
when the Vout-Vout1- Δ V1 is greater than zero, the first voltage comparison operational amplifier works, and the first voltage comparison operational amplifier outputs a forward ripple current Itran according to the amplitude of the Vout-Vout1- Δ V1;
when the Vout1-Vout- Δ V2 is greater than zero, the second voltage comparison operational amplifier operates, and the second voltage comparison operational amplifier outputs a reverse ripple current Itran according to the amplitudes of the Vout1-Vout- Δ V2.
8. The system according to claim 6 or 7, wherein the ramp generator is specifically configured to generate a feedback current Iramp by superimposing the ripple current iran and a preset reference current Iref, and generate the feedback tooth-shaped voltage Vramp according to an amplitude of the feedback current Iramp.
9. The system of claim 8, further comprising an error amplifier EA for generating a feedback voltage Vcomp from a reference voltage Vref and the divided output voltage Vout;
correspondingly, the voltage generating device is configured to generate a pulse width signal according to a difference between the feedback tooth-shaped voltage Vramp and the feedback voltage Vcomp, and modulate the pulse width signal to generate the transient response output voltage Vout of the voltage-mode buck converter.
10. The system of claim 9, further comprising a compensation network compensation, wherein the feedback voltage Vcomp is a voltage compensated by the compensation network compensation.
11. The system of claim 7, wherein the first and second voltage comparison op-amps each comprise a transconductance op-amp and a mirror current circuit;
the output stages of the two output MOS tubes of the transconductance operational amplifier are asymmetric to generate offset voltage; the first input threshold voltage delta V1 and the second input threshold voltage delta V2 are offset voltages of the first voltage comparison operational amplifier and the second voltage comparison operational amplifier in sequence;
the mirror current circuit is located at the output end of the voltage comparison operational amplifier, and the current of the mirror current circuit is unidirectional.
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| PCT/CN2016/084276 WO2017067174A1 (en) | 2015-10-22 | 2016-06-01 | Method and system for enhancing load transient response of voltage-mode buck converter |
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| CN108233692A (en) * | 2017-12-19 | 2018-06-29 | 晶晨半导体(上海)股份有限公司 | A kind of soft starting circuit of switching regulator |
| CN108304022B (en) * | 2017-12-19 | 2020-12-25 | 晶晨半导体(上海)股份有限公司 | Overcurrent protection circuit of switching regulator |
| CN108566073B (en) * | 2017-12-19 | 2020-10-09 | 晶晨半导体(上海)股份有限公司 | Transient response circuit of switching regulator |
| CN108306504B (en) * | 2017-12-19 | 2020-10-09 | 晶晨半导体(上海)股份有限公司 | Transient response circuit of switching regulator |
| CN114556762A (en) * | 2019-10-31 | 2022-05-27 | 华为技术有限公司 | Switching power supply converter |
| US11258297B2 (en) * | 2019-12-30 | 2022-02-22 | Schneider Electric It Corporation | Inverter control strategy for a transient heavy load |
| CN117879348B (en) * | 2023-04-26 | 2024-06-11 | 杭州顺元微电子有限公司 | Step-down DCDC converter |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101548252A (en) * | 2006-08-18 | 2009-09-30 | 美国快捷半导体有限公司 | Power converter with hysteretic control |
| CN101741248A (en) * | 2008-11-18 | 2010-06-16 | 英特赛尔美国股份有限公司 | Adaptive PWM pulse positioning for fast transient response |
| CN203445787U (en) * | 2013-09-05 | 2014-02-19 | 成都芯源系统有限公司 | Power Converter, Clock Module, and Control Circuit |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000032744A (en) * | 1998-07-08 | 2000-01-28 | Toyota Autom Loom Works Ltd | Dc-dc converter and its control method |
| US7132820B2 (en) * | 2002-09-06 | 2006-11-07 | Intersil Americas Inc. | Synthetic ripple regulator |
| CN101546957B (en) * | 2008-03-24 | 2012-07-25 | 凹凸电子（武汉）有限公司 | DC to DC converter having controller and control method thereof |
| TWI354193B (en) * | 2009-12-01 | 2011-12-11 | Ind Tech Res Inst | Voltage converting circuit and method thereof |
| CN103023324B (en) * | 2012-11-21 | 2015-04-08 | 东南大学 | Fast transient response DC-DC (direct-current to direct-current) switching converter with high load regulation rate |
| US8941368B2 (en) * | 2013-03-07 | 2015-01-27 | Analog Devices Technology | Skip mode method and system for a current mode switching converter |
| CN103683928A (en) * | 2013-11-27 | 2014-03-26 | 苏州贝克微电子有限公司 | Leading phase compensating circuit integrated with switching regulator |
| CN103683935A (en) * | 2013-12-03 | 2014-03-26 | 成都芯源系统有限公司 | Switch mode power supply and control circuit and control method thereof |
| CN104377958A (en) * | 2014-11-27 | 2015-02-25 | 电子科技大学 | Transient response intensifier circuit for switching power supply |
-
2015
- 2015-10-22 CN CN201510690108.2A patent/CN106612070B/en active Active
-
2016
- 2016-06-01 WO PCT/CN2016/084276 patent/WO2017067174A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101548252A (en) * | 2006-08-18 | 2009-09-30 | 美国快捷半导体有限公司 | Power converter with hysteretic control |
| CN101741248A (en) * | 2008-11-18 | 2010-06-16 | 英特赛尔美国股份有限公司 | Adaptive PWM pulse positioning for fast transient response |
| CN203445787U (en) * | 2013-09-05 | 2014-02-19 | 成都芯源系统有限公司 | Power Converter, Clock Module, and Control Circuit |
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Application publication date: 20170503 Assignee: Xi'an Chris Semiconductor Technology Co. Ltd. Assignor: SHENZHEN ZTE MICROELECTRONICS TECHNOLOGY CO., LTD. Contract record no.: 2019440020036 Denomination of invention: Load transient response enhancement method and system for voltage-mode buck converter Granted publication date: 20190430 License type: Common License Record date: 20190619 |